Lubricator valves are valves used downhole to allow long assemblies to be put together in the well above the closed lubricator valve with well pressure further below the closed lubricator valve. These valves are frequently used in tandem with sub-surface safety valves to have redundancy of closures against well pressures below.
Lubricator assemblies are used at the surface of a well and comprise a compartment above the wellhead through which a bottom hole assembly is put together with the bottom valve closing off well pressure. These surface lubricators have limited lengths determined by the scale of the available rig equipment. Downhole lubricators simply get around length limitations of surface lubricators by using a lubricator valve downhole to allow as much as thousands of feet of length in the wellbore to assemble a bottom hole assembly.
In the past ball valves have been used as lubricator valves. They generally featured a pair of control lines to opposed sides of a piston whose movement back and forth registered with a ball to rotate it 90 between an open and a closed position. Collets could be used to hold the ball in both positions and would release in response to control pressure in one of the control lines. An example of such a design can be seen in U.S. Pat. Nos. 4,368,871; 4,197,879 and 4,130,166. In these patents, the ball turns on its own axis on trunnions. Other designs translate the ball while rotating it 90 degrees between and open and a closed position. One example of this is the 15K Enhanced Landing String Assembly offered by the Expro Group that includes such a lubricator valve. Other designs combine rotation and translation of the ball with a separate locking sleeve that is hydraulically driven to lock the ball turning and shifting sleeve in a ball closed position as shown in U.S. Pat. No. 4,522,370. Some valves are of a tubing retrievable style such as Halliburton's PES® LV4 Lubricator Valve. Lock open sleeves that go through a ball have been proposed in U.S. Pat. No. 4,449,587. Other designs, such as U.S. Pat. No. 6,109,352 used in subsea trees have a rack and pinion drive for a ball and use a remotely operated vehicle (ROV) to power the valve between open and closed positions claiming that either end positioned is a locked position but going on to state that the same ROV simply reverses direction and the valve can reverse direction. Ball valves that are not used downhole are shown in U.S. Pat. Nos. 6,695,286; 4,289165 and 5,417,405.
What is lacking and addressed by the present invention is a more elegant solution to a downhole ball type valve for use in applications such as a barrier or in a sand control application, for a few examples. The present invention is directed to a mechanical actuation of a ball valve through a shifting of a sleeve that can in one instance be actuated with a shifting tool run on wireline. It further provides a pressure equalizing mechanism on the actuation assembly in the event the ball is closed and pressure differential comes from above the ball. The pressure is equalized on the actuation mechanism but not across the closed ball so as to prevent pressure differential from moving a sleeve in the actuation mechanism that would otherwise rotate the ball open. These and other features of the present invention will become more readily apparent to those of ordinary skill in the art from a review of the description of the preferred embodiment that appears below in conjunction with the associated drawings while recognizing that the appended claims are the full measure of the invention.